Means for making a lamp shade



G. w. BORKLAND 2,797,439

MEANS FOR MAKING A LAMP SHADE July 2, 1957 Original Filed Dec. 21, 19492 Sheets-Sheet 1 To 501/905 0F ELECTRIC CURRENT .iP/lcs 1154 m?ELEME/VZZS 70 V/ICUUM PUMP 1 6 INVENTOR.

July 2, 1 57 G. w. BORKLAND 2,797,439

- MEANS FOR MAKING A LAMP SHADE Original Filed Dec. 21, 1949 2Sheets-Sheet 2 TO JOUFCEO/C 65 5256mm CURRENT 67 JP/JCE 77 L HEATER IELEMENTE INVENTOR.

1952, Serial No. 318,506

3 Claims. (Cl. rs-Ais This invention relates, generally, to means formaking a new article of manufacture, and in particular it relates toapparatus for forming tubular articles, such as lamp shades. Thisapplication is a division of application Serial No. 134,325, filedDecember 21, 1949, now abandoned.

Among 'the objects of this invention are: To provide a tubular article,such as a lamp shade, 'of thermoplastic material having one or moreembossinents formed permanently therein; to provide such an articlehaving a generally conical shape; to employ a flat sheet of material forthis purpose; to curve the flat sheet generally to the shape desired forthe ultimate article; to deform one or more areas of the sheet so shapedin order to provide the embo'ssnient of embossmentsj to heat the sheetto facilite its permanent deformation; to deform the sheet by applyingfluid pressure to the area or areas to be deformed; to hold the ends ofthe article against lateral slipping while the' deformation operation isbeing performed; and to remove the deformed and set article from the dieemployed in forming it by curling one or both of the free ends inwardlyor outwardly to decrease or increase its diameter as the case may be.

Other objects of this invention will, in part, be obvious and in partappear hereinafter.

For a more complete understanding of the nature and scope 'of thisinvention, reference may be had to the following detailed description,taken together with the accompanying drawings, in which:

, Figure 1 is a plan view of an arcuate sheet of 'thermoplastic materialwhich is employed 'in practicing this invention;

Figure 2 is a perspective view of a frusto conical configuration intowhich the sheet shown in Figure 1 can be curved;

Figure 3 is a cross sectional view, somewhat diagrammatic in character,of a die and plug which can be used in practicing this invention;

Figure 4 is a view, in side elevation, of a lamp shade which may beformed in accordance with this invention;

Figure 5 is a detail sectional view taken generally along the line 5-5of Figure 4;

Figure -6 is a vertical sectional view, somewhat diagra-rrimatic incharacter, showing an alternate form of die and socket constructionwhich maybe employed in practicing this invention;

Figure 7 is a vertical sectional view of a lamp shade which may beformed on the die and socket construction shown in Figure 6;

Figure 8 is a top plan view of the die shown in Figure 3 andillustratinghow the'form-ed sheet can be removed.

Referring now particularly to Figures 1 and 2 of the drawings, it willbe noted that the reference character 10 designates an arcuate sheet ofthermoplastic material. It may be curved so as to form a trusts-conicalconfiguration indicated, generally, at 11. This is accomplished bycurving the sheet ltl until the ends 12 overlap each other as indicatedat 13. lf'desired, the ends 12 can be ar- 2,797,439 Patented July 2,1957 2 ranged so as to form a buttjoint and they can be secured togetherin any suitable manner such as by overlying a strip of the same materialas may be desired.

As indicated the arcuate sheet 10 is formed of'theimoplastic material.Also it may be formed of semithermo plastic material or reinforcedthermoplastic material, for example, cellulose acetate, vinyl resins,ethyl cellulose, methyl methacrylate .resi'n, etc.

In order to provide one or more permanent embossme'nts in the arcuatesheet 10, it is curved into the frustoconical configuration 11 and thenis placed in a female die that is indicated, generally, at '16. The die16 includes an upper die portion 17wand a lower die portion 18. Theupper die portion 17 has a conical concave surface 19 the general"outline of which conforms to the outer surface of the frusto-conic'alconfiguration 11. As shown the frusto-conical configuration 11 isinserted in the conical concave recess provided by the surface 19 sothat it fits snugly therewith. The thickness of the material making upthe frusto-conical -configuration 11 is shown at a somewhat exaggeratedscale. It Will be understood that it may me of the-order of a fewthousandths of an inch thick asv may be required. Of course it may bethicker where a heavier or thicker article is to be formed.

Specifically the embossinents'are provided in the frustoconicalconfiguration 11 by providing recesses or cavities 20 inthe'co'nicalconcavesurface 19. The shape of these -recesses or cavities2i may be regular or irregular as may be desired. For example, they maybe shaped so as to form a ribbon configiration, a flower, a hemisphere,etc. It will be. understood that one or more recesses or cavities 29 maybe provided depending upon the particular design which is to be formedon the frusto conical configuration 11. v

As will appear hereinafter, the frusto-conical configuration in situ isheated and fluid pressure-is applied to the portions thereof overlyingthe recesses or cavities 20 so as to deform ,thes'e portions thereinto.In order to permit the evacuation 'of the recesses or cavities 20conduits 21 connect therewith and open into an annular chamber 22. Asshown in Figure 3 the annular chamber may be con nected by a conduit 23through a valve 24 to a vacuum pump.

Near the lower end of the conical concave surface 19 there is provided ashallow annular groove 27 which may be connected by a conduit 28 to theannular chamber 22. Theannula'r groove 27 is provided in order to form acorrespondingly shaped groove in the upper end of the frusto-conicalconfiguration 11 for the purpose of receiving a support member, such asa support ring, which may be employed in conventional manner forsupporting the lamp shade'in position on a lamp.

With a view to rigidifying the lower portion of the lamp shade, anannular groove 29 may beprovided in the conical concave surface 19 andit may be connected by a conduit 30 to the annular chamber 22. Thisforms an annular groove or a radially outwardly extending rib in thelower portion of the lamp shade and acts to rigidity this portion andmaintain it in the desired circular shape.

Cooperating with the die 16 is a holding and heating plug that isindicated, generally, at 33. The plug 33 includes upper and lowerfrusto-conical holding members 34 and 35 which are formed of heatresisting insulating material. They are mounted in spaced relation on asuitable operating rod 36 which can be moved either mechanically ormanually as may be desired. The peripheries of the members 34 and 35 areshaped so as to engage the respective ends of the frusto-conicalconfiguration 11 located, as shown, in the die 16 for holding themagainst lateral slipping while the heating and forming operations arebeing performed. Space heater elements 37 extend between the members 34and 35 and are arranged to be energized by a flexible conductor assembly33 which it will be understood is connected to a source of electriccurrent as illustrated. It will be understood that the plug 33 ismovable downwardly into the die 16 and upwardly away therefrom asindicated by the double headed arrow 39.

In operation, the arcuate sheet is curved to form the conicalconfiguration 11 and this is placed on the conical concave surface 19 ofthe die 16. The ends 12 may overlap, as indicated at 13, or they may beplaced in abutting relation as may be desired. 7 If desired, the valve24 can be opened to apply vacuum to the recesses or cavities 20 and tothe annular grooves 27 and 29. However, the material is not deformedbecause it is not yet heated to the plastic state.

Now the plug 33 is inserted in the cavity bounded by the conical concavesurface 19 with the holding members 34 and 35 in engagement with therespective ends of the conical configunation 11 and the joint 13 iscovered to prevent loss of pressure. This engagement takes place abovethe annular groove 29 and below the annular groove 27 and along thejoint 13. The space heater elements 37 are energized sufficiently toheat the material in the areas overlying the recesses or cavities 20 andthe annular grooves 27 and 29 sufficiently to permit these areas to bedeformed into these recesses or cavities and grooves. The deformationtakes place as a result of the atmospheric pressure applied to the sidesof the material opposite the recesses or cavities 20 and the grooves 27and 29.

As soon as the material has been suitably deformed, the space heaters 37are deenergized, the deformed sheet 10 is allowed to cool, and then theplug 33 is withdrawn. The resulting article can be removed readily bypicking up one end 41 and curling it inwardly as shown in Figure 8, soas to reduce the diameter of the lamp shade. Then it can be Withdrawnreadily upwardly.

Instead of using vacuum and atmospheric pressure to provide the desireddifferential pressure, fluid pressure, such as air pressure or steam,can be applied to the inside of the frusto-conical configuration 11 inthe die 16, the holding members 34 and 35 engaging the ends and thejoint 13 so as to provide a fluid-tight construction. Instead of usingan electrical source of heat, the heat may be supplied by other meanssuch as steam. In addition, instead of using space heater elements,infra-red bulbs or like units can be employed to provide spot heating.

The resultant product formed by the process and apparatus abovedescribed is illustrated as a lamp shade at 42 in Figure 4. Embossments43 are formed in the outer surface and extend outwardly in conformitywith the shapes of the recesses or cavities 20. An annular groove 44 isformed near the upper end for receiving a support ring 45. It will beunderstood that the ring 45 can be snapped in place if the ends 12 ofthe sheet have been secured together. Also it can be placed in positionand thereafter the ends secured together. Near the lower end an annulargroove 46 is formed which serves to rigidity this portion of the lampshade 42. If desired the upper and lower end portions 47 and 48 may betrimmed off. Also these portions can be employed for applying a suitablefringe or border of cloth or other material as may be desired.

It will be seen that the foregoing method and apparatus provide astructure which is inherently self-supporting and requires no ribs orframework or supporting structure.

While the sheet 10 is in flat form it can be decorated, printed, orsilk-screened depending upon the colors desired for the embossments 43.

In the formation of the lamp shade 42 as described hereinbcfore theembossments 43 extend outwardly from the surface of the conicalconfiguration 11. Where it is desired to have the embossments extendinwardly, the forming apparatus illustrated in Figure 6 may be employed.

As there shown a male die 51 is provided which includes 'suflicient topermit it to be deformed by fluid pressure.

a frusto-conically shaped support 52 the outer surface 53 i of which isgenerally cone shaped and conforms to the shape of the inner surface ofthe frusto-conical configuration 11. As shown, this configuration ispositioned on the surface 53 of the support 52. In the surface 53 thereare provided one or more recesses or cavities 54 the shape of which isdetermined by the shape of the embossrnent that is desired. The recessor recesses 54 may be regularly or irregularly shaped as will beunderstood.

The area or areas of the frusto-conical configuration 11 overlying therecess or recesses 54 are arranged to be deformed inwardly by fluidpressure when heated in a manner to be described. In order to permitthis action openings 55 are provided for placing the recesses orcavities 54 in communication with a chamber 56 that is formed in the die51. For evacuating the chamber 56 a conduit 57 is provided in which avalve 53 may be positioned. On opening of the valve 58 the conduit 57 isplaced in communication with a vacuum pump, as illustrated, and thechamber 56 is evacuated. If desired, the valve 58 can be omitted and thevacuum applied continuously to hold the configuration 11 in place.

Cooperating with the die 51 is a socket that is indicated, generally, at63. It includes upper and lower holding members 64 and 65 that areformed of insulating material and each has a concave conical surface 66and 67, respectively. The surfaces 66 and 67 are arranged to engageintimately the upper and lower ends of the conical configuration 11 onthe die 51 for the purpose of holding them against lateral slipping.

In order to heat the sheet of thermoplastic material making up theconical configuration 11, space heater elements 74 are supported by theholding members 64 and 65 and are arranged in a generally conical shapeso as to heat uniformly the surface of the plastic material. A flexibleconductor 75 is arranged to connect the space heater elements 74 to asuitable source of electric current as illustrated. The holding members64 and 65 are supported in spaced relation by a cylindrical support 76.

In operation the socket 63 is arranged to be moved downwardly andupwardly as indicated by the double headed arrow 77. After the sheet 10of thermoplastic material is curved to form the conical configuration11, it is placed on the die 51 as shown in Figure 6. Then the valve 58may be opened and the chamber 56 can be evacuated. It may be that theconical configuration 11 will not provide a fluid-tight fit with theconical surface 53 at this time but no forming action can take placebecause the material has not been heated to a temperature Now the socket63 is moved downwardly until the conical surfaces 66 and 67 engage theupper and lower ends of the conical configuration 11, respectively.Sufficient pressure is exerted so that a fluid-tight seal now isprovided between the inner surface of the conical configuration 11 andthe outer conical surface 53. The space heater elements 74 are energizedand sufiicient heat is applied to the outer surface of the conicalconfiguration 11 as will permit the areas thereof overlying the recessesor cavities 54 to be deformed. Because of the evacuation of the recessesor cavities 54, the areas of the thermoplastic material overlying themare drawn or stretched thereinto and conform to the shape thereof.

After the material has been deformed into the recesses or cavities 54,the valve 58 is closed, the space heater elements 74 are deenergized andthe formed material is allowed to cool. Thereafter the socket 63 ismoved upwardly. If the formed material does not lift readily from thedie 51, one end of it may be grasped and it may be curled outwardly awaytherefrom as contrasted with the inward curling shown in Figure 8.

The resulting lamp shade construction is illustrated at 73 in Figure 7.Inwardly extending embossments 79 are formed permanently therein. Theirshapes correspond to the shapes of the recesses or cavities 54 used forforming the same. As before, the sheet employed for forming a lamp shade78 can have imprinted thereon various colored designs which, whenembossed, provide the desired decoration.

It will be understood that provision can be made for relative movementbetween the die 16 and the plug 33 in any suitable manner. Either may bestationary and the other movable or both may be movable. Likewisesuitable means can be provided for effecting relative movement betweenthe die 51 and the socket 63. Either may be stationary and the othermovable or both may be movable toward and away from the other.

Since certain further changes can be made in the foregoing method andapparatus and different embodiments of the invention can be made withoutdeparting from the spirit and scope thereof, it is intended that allmatter set forth in the foregoing description or shown in theaccompanying drawings will be interpreted as illustrative and not in alimiting sense.

What is claimed as new is:

1. Apparatus for making conical articles, such as lamp shades, fromthermoplastic sheet material comprising, in combination, a die having acontinuous conical surface arranged and adapted to receive the sheet inpreformed conical shape and having one or more cavities in saidcontinuous surface; a cooperating relatively movable member for said dieincluding spaced retaining means for engaging the ends of the coneshaped sheet and holding the same in engagement with said conicalsurface to prevent lateral slipping, and heating means between saidretaining means for heating said sheet in situ to a temperaturesuflicient to permit it to be deformed; and means for applying a greaterfluid pressure to the side of said sheet opposite said cavity orcavities than is applied to the other side to deform the area or areasoverlying the same thereinto.

2. Apparatus for making conical articles, such as lamp shades, fromthermoplastic sheet material comprising, in combination, a die having acontinuous concave conical surface for receiving a conically shapedsheet and having one or more cavities in said continuous surface shapedto form one or more decorative embossments on said sheet, vacuum meansconnected to said cavity or cavities for evacuating the same; and plugmeans relatively movable with respect to said die including spacedcircular retaining members for engaging the ends of the conical sheetand holding the same in engagement with said conical surface againstlateral slipping, and heating means between said retaining members forheating at least the portion or portions of said sheet overlying saidcavity or cavities to a temperature suflicient to permit the same to bedeformed by the fluid pressure applied thereto on evacuation of saidcavity or cavities.

3. Apparatus for making conical articles, such as lamp shades, fromthermoplastic sheet material comprising, in

combination, a die having a continuous convex conical surface forreceiving a conically shaped sheet and having one or more cavities insaid continuous surface shaped to form one or more decorativeembossments on said sheet, vacuum means connected to said cavity orcavities for evacuating the same; and socket means relatively movablewith respect to said die including spaced circular retaining members forengaging the ends of the conical sheet and holding the same inengagement with said conical surface against lateral slipping, andheating means between said retaining members for heating at least theportion or portions of said sheet overlying said cavity or cavities to atemperature sufficient to permit the same to be deformed by the fluidpressure applied thereto on evacuation of said cavity or cavities.

References Cited in the file of this patent UNITED STATES PATENTS Re.23,171 Borkland Nov. 29, 1949 1,475,623 Egerton Nov. 27, 1923 1,588,933Bolger June 15, 1926 1,885,951 Salisbury Nov. 1, 1932 1,989,015 McKellipJan. 22, 1935 2,415,504 MacDonald Feb. 11, 1947 2,478,165 Collins Aug.2, 1949 2,493,439 Braund Jan. 3, 1950

